Field of the Disclosure
The present disclosure relates to a radar apparatus and a corresponding radar method. Further, the present disclosure relates to a processing apparatus and method for use in such a radar apparatus and method, respectively. Still further, the present disclosure relates to a computer program for implementing said processing method and to a computer readable non-transitory medium storing such a computer program.
Description of Related Art
Synthetic aperture radar (SAR) is a common technique used in radar applications like remote sensing or radar imaging because it allows increasing the effective aperture of a certain antenna by moving it over the surface to be sensed/imaged, or the scatter to be detected. As the radar antenna passes over a given scatter, many pulses are transmitted from the transmitter antenna in sequence and the reflected signals are recorded by a receiver antenna. By combining these individual signals, a synthetic aperture is created which provides a much improved resolution in the azimuth resolution. The received echoes contain full phase and amplitude information of the scene reflectivity, but the image reconstructed from that signals is unfocused, due to the phase differences among the acquired signals caused by the different propagation time at each antenna position. Using signal processing techniques, the image is focused by correcting these phase differences, to obtain the improved resolution provided by the antenna movement. Another important benefit of SAR is that the theoretical achievable spatial resolution in the direction of the movement only depends on the physical size of the antenna in the same direction.
The SAR technique is traditionally used by mounting an antenna or array of antennas in a spacecraft or airborne for applications like earth observation, topographic missions, agriculture, military recognition or surveillance, etc. The recent advances in the millimeter waves frequency range (30-300 GHz) towards miniaturization and system integration, mainly driven by the introduction of radar based driver assistance systems in the automotive industry, together with the growing demand for security applications for concealed weapons or explosive substances detection, have triggered an intense activity in the area of radar imaging. For such applications it is desirable to achieve improved resolution but in the two dimensions of the scene. This can be done by applying SAR in both directions and then synthesize the 2D image.
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor(s), to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.